Bottom Line:
Due to the rapid advent in genomics technologies and attention to ecological risk assessment, the term "ecotoxicogenomics" has recently emerged to describe integration of omics studies (i.e., transcriptomics, proteomics, metabolomics, and epigenomics) into ecotoxicological fields.Ecotoxicogenomics is defined as study of an entire set of genes or proteins expression in ecological organisms to provide insight on environmental toxicity, offering benefit in ecological risk assessment.These approaches enable us to address adverse phenotypic outcomes linked to particular gene function(s) and mechanistic understanding of aquatic ecotoxicology as well as exploration of useful biomarkers.

ABSTRACTDue to the rapid advent in genomics technologies and attention to ecological risk assessment, the term "ecotoxicogenomics" has recently emerged to describe integration of omics studies (i.e., transcriptomics, proteomics, metabolomics, and epigenomics) into ecotoxicological fields. Ecotoxicogenomics is defined as study of an entire set of genes or proteins expression in ecological organisms to provide insight on environmental toxicity, offering benefit in ecological risk assessment. Indeed, Daphnia is a model species to study aquatic environmental toxicity designated in the Organization for Economic Co-operation and Development's toxicity test guideline and to investigate expression patterns using ecotoxicology-oriented genomics tools. Our main purpose is to demonstrate the potential utility of gene expression profiling in ecotoxicology by identifying novel biomarkers and relevant modes of toxicity in Daphnia magna. These approaches enable us to address adverse phenotypic outcomes linked to particular gene function(s) and mechanistic understanding of aquatic ecotoxicology as well as exploration of useful biomarkers. Furthermore, key challenges that currently face aquatic ecotoxicology (e.g., predicting toxicant responses among a broad spectrum of phytogenetic groups, predicting impact of temporal exposure on toxicant responses) necessitate the parallel use of other model organisms, both aquatic and terrestrial. By investigating gene expression profiling in an environmentally important organism, this provides viable support for the utility of ecotoxicogenomics.

ijms-16-12261-f003: A scheme illustrating the utility of gene expression signatures to explore the possible mode of toxicity of an unknown environmental toxicant in an aquatic model organism (Daphnia spp.).

Mentions:
While ecotoxicogenomic studies have tended to focus on mechanisms, mechanistic research has not been conducted to the exclusion of fingerprinting approaches and biomarker discovery (Figure 3) [2]. Many in the field have used their transcriptomic data to both explore mechanisms and attempt to identify transcriptional fingerprints or biomarkers potentially indicative of specific types of exposure or effects. For example, Poynton et al. [37] identified distinct expression profiles in Daphnia magna for three different metals, found support for known mechanisms of metal toxicity, and postulated inhibition of chitinase activity by zinc as a novel mode of action [37].

ijms-16-12261-f003: A scheme illustrating the utility of gene expression signatures to explore the possible mode of toxicity of an unknown environmental toxicant in an aquatic model organism (Daphnia spp.).

Mentions:
While ecotoxicogenomic studies have tended to focus on mechanisms, mechanistic research has not been conducted to the exclusion of fingerprinting approaches and biomarker discovery (Figure 3) [2]. Many in the field have used their transcriptomic data to both explore mechanisms and attempt to identify transcriptional fingerprints or biomarkers potentially indicative of specific types of exposure or effects. For example, Poynton et al. [37] identified distinct expression profiles in Daphnia magna for three different metals, found support for known mechanisms of metal toxicity, and postulated inhibition of chitinase activity by zinc as a novel mode of action [37].

Bottom Line:
Due to the rapid advent in genomics technologies and attention to ecological risk assessment, the term "ecotoxicogenomics" has recently emerged to describe integration of omics studies (i.e., transcriptomics, proteomics, metabolomics, and epigenomics) into ecotoxicological fields.Ecotoxicogenomics is defined as study of an entire set of genes or proteins expression in ecological organisms to provide insight on environmental toxicity, offering benefit in ecological risk assessment.These approaches enable us to address adverse phenotypic outcomes linked to particular gene function(s) and mechanistic understanding of aquatic ecotoxicology as well as exploration of useful biomarkers.

ABSTRACTDue to the rapid advent in genomics technologies and attention to ecological risk assessment, the term "ecotoxicogenomics" has recently emerged to describe integration of omics studies (i.e., transcriptomics, proteomics, metabolomics, and epigenomics) into ecotoxicological fields. Ecotoxicogenomics is defined as study of an entire set of genes or proteins expression in ecological organisms to provide insight on environmental toxicity, offering benefit in ecological risk assessment. Indeed, Daphnia is a model species to study aquatic environmental toxicity designated in the Organization for Economic Co-operation and Development's toxicity test guideline and to investigate expression patterns using ecotoxicology-oriented genomics tools. Our main purpose is to demonstrate the potential utility of gene expression profiling in ecotoxicology by identifying novel biomarkers and relevant modes of toxicity in Daphnia magna. These approaches enable us to address adverse phenotypic outcomes linked to particular gene function(s) and mechanistic understanding of aquatic ecotoxicology as well as exploration of useful biomarkers. Furthermore, key challenges that currently face aquatic ecotoxicology (e.g., predicting toxicant responses among a broad spectrum of phytogenetic groups, predicting impact of temporal exposure on toxicant responses) necessitate the parallel use of other model organisms, both aquatic and terrestrial. By investigating gene expression profiling in an environmentally important organism, this provides viable support for the utility of ecotoxicogenomics.